According to the ICC Year 2001 Piracy Report, more than 330 attacks on seafaring vessels were reported in 2001 - down by a quarter compared to 2000 but 10 percent higher than 1999 and four times the 1991 figure. Piracy rose 40 percent between 1998 and 1999 alone. Sixteen ships - double the number in 2000 - were captured and taken over in 2001. Eighty seven attacks were reported during the first quarter of 2002 - up from 68 in the corresponding period the year before. Seven of these were hijackings - compared to only 1 in the first quarter of 2001. Nine of every 10 hijacked ships are ultimately recovered, often with the help of the IMB. Many masters and shipowners do not report piracy for fear of delays due to protracted investigations, increased insurance premiums, bad publicity, and stifling red tape. The number of unreported attacks in 1999 was estimated by the World Maritime Piracy Report to be 130. According to "The Economist", the IMO believes that half of all incidents remain untold. Still, increased patrols and international collaboration among law enforcement agencies dented the clear upward trend in maritime crime - even in the piracy capital, Indonesia. The number of incidents in the pirate-infested Malacca Straits dropped from 75 in 2000 to 17 in 2001 - though the number of crew "kidnap and ransom" operations, especially in Aceh, has increased. Owners usually pay the "reasonable" amounts demanded - c. $100,000 per ship. Contrary to folklore, most ships are attacked while at anchor. Twenty one people, including passengers, were killed in 2001 - and 210 taken hostage. Assaults involving guns were up 50 percent to 73 - those involving mere knives down by a quarter to 105. Piracy seems to ebb and flow with the business cycles of the host economies. The Asian crisis, triggered by the freefall of the Thai baht in 1997-8, gave a boost to East Asian maritime robbers. So did the debt crises of Latin America a decade earlier. Drug transporters - armed with light aircraft and high speed motorboats - sometimes double as pirates during the dry season of crop growth. Pirates endanger ship and crew. But they often cause collateral damage as well. Pirates have been known to dump noxious cargo into the sea, or tie up the crew and let an oil tanker steam ahead, its navigational aides smashed, or tamper with substances dangerous to themselves and to others, or cast crew and passengers adrift in tiny rafts with little food and water. Many shipowners resorted to installing on-board satellite tracking systems, such as Shiploc, and aircraft-like "black boxes". A bulletproof life vest, replete with an integral jagged edged knife, was on display in the millennium exhibition at the Millennium Dome two years ago. The International Maritime Organization (IMO) is considering to compel shipowners to tag their vessels with visibly embossed numbers in compliance with the Safety of Life at Sea Convention.